Polymerization of unsaturated compounds with aromatized linoleic acid



United States Patent 3,269,968 POLYMERIZATION 0F UNSATURATED COM- POUNDSWITH AROMATIZED LINOLEIC ACID Malcolm E. Hannah, Jr., Pensacola, Fla.,assignor, by

mesne assignments, to Tenneco Chemicals Inc., a corporation of DelawareNo Drawing. Filed May 21, 1962, Ser. No. 196,435 20 Claims. (Cl.260-23.7)

This invention relates to an improved process for the emulsionpolymerization of water insoluble, unsaturated organic compounds whiledispersed in an aqueous medium. More particularly, the present inventionrelates to the use of a novel emulsifying agent in the emulsionpolymerization reaction.

It is well known that unsaturated organic compounds containing thegroup, CH =C may be polymerized while dispersed in an aqueous medium. Alarge number of monomeric materials may be polymerized individually orin various combinations to form relatively large linear polymers. Suchmonomers include the aliphatic conjugated diolefins, or 1,3-butadienecompounds such as butadiene-1,3, 2,3-dimethyl-1,3-butadiene, isoprene,chloroprene, methylchloroprene, bromoprene and the like; the arylolefins such as styrene, alpha-methyl-styrene, p-methylalpha-methylstyrene, p-chlorostyrene and the like; as well as acrylicacid, methacrylic acid, methyl acrylate methyl methacrylate, butylmethacrylate, vinyl acetate, vinyl chloride, vinylidene chloride, andother unsaturated compounds of this type. Soaps of fatty acids and rosinacids have been used extensively as emulsifying agents for dispersingthe monomeric material in the aqueous medium and forming oil-in-watertype emulsion.

In general, the fatty acid soaps which have been used are the potassiumor sodium soaps of higher fatty acids containing from 14 to 20 carbonatoms in the molecule such as myristic, palmitic, oleic, or stearic acidor mixtures thereof. The potassium soap of hydrogenated tallow fattyacids has been used extensively. This soap is primarily a mixture of thepotassium salts of saturated fatty acids containing 14 to 18 carbonatoms per molecule. The potassium soap of hydrogenated tallow fattyacids does produce a relatively fast polymerization rate. These fattyacid soaps, particularly the hydrogenated tallow fatty acid soaps, arenot sufficiently water-soluble and are quite diflicult to remove fromthe polymerization product which is an undesirable characteristic. Thesoaps of acids derived from many naturally occurring oils and fats aswell as the soap of tall oil fatty acids cannot be used as the acidscontain substantial amounts of polyunsaturated fatty acids whichseriously interfere with the polymerization reaction. Soaps ofpolyunsaturated fatty acids slow down the rate of reaction and tend toreact with material being polymerized. The presence of polyunsaturatedacids in synthetic rubber interferes with curing the rubber.

In accordance with the present invention it has been found that thealkali metal salts of aromatized linoleic acid may be used to advantageas emulsifying agents for the polymerization of the aforesaidunsaturated organic compounds. The aromatized linoleic acid soap may beused alone or in combination with soaps of other fatty acids containing14 to 20 carbon atoms. An important practical advantage is that tall oilfatty acids, and fatty acid mixtures derived from siccative oils, aswell as other fatty acid mixtures containing polyunsaturated acids canbe used in the production of soaps for the aqueous polymerizationprocess after aromatization of the linoleic acid and/ or otherpolyunsaturated acids. The resulting fatty acid mixtures will usuallycontain at least by weight of the aromatized linoleic acid and at least2 5% by weight of oleic. The presence of some oleic acid is desirable,however, oleic acid need not be present. The mixture of ice acids shouldcontain less than 5% by weight of polyunsaturated fatty acids which areacids containing more than one carbon to carbon double bond. Soaps ofaromatized linoleic acid or mixtures of this acid and other fatty acidsmay be used to obtain polymerization rates equal to that obtained withhydrogenated tallow fatty acid soaps. In addition the aromatizedlinoleic acid soaps can be used with rosin soaps as emulsifying agentsin the production of synthetic rubber or other copolymers orhomopolymers to produce results as good as those obtained with a mixtureof hydrogenated tallow fatty acid soap and rosin soap. The rosin soapmay be the alkali soap of rosin, either modified or unmodified, or oftall oil rosin acids, preferably, but not necessarily, disproportionedtall oil rosin acids.

The aromatized linoleic acid may be prepared by the aromatization ofsubstantially pure linoleic acid or by aromatization of the linoleicacid when mixed with other fatty acids as is the case with acids derivedfrom oils such as soybean, sunflower, peanut and fish oils, or the like.Tall oil fatty acids may be used to advantage as a starting material.Aromatized linoleic acid is a mixture of acids having a characteristicand strong infrared absorption band in the 13.3 region and having thefollowing structural formula:

in which the sum of x and y is equal to 10 and y is at least 5 and lessthan 8. The aromatized linoleic acid may be prepared by any suitableprocess and may be prepared, for example, as described in the articleentitled The Aromatization of Linoleic Acid With Palladium Catalystappearing in The Journal of The American Oil Chemists Society, volume33, No. 12, December 1956, pages 609 through 614.

The emulsion polymerization of the monomeric material may be carried outwith the present soaps in the same manner as when the heretofore knownsoaps have been used and a batch-type, semi-continuous or continuousprocess may be used. Generally, various additives Will be used topromote the reaction, control the chain length of the polymer, andproduce a polymer having the desired properties. The additives used varydepending upon the monomer being polymerized and other factors. Forexample, in the copolymerization of butadiene-1,3 and styrene to producesynthetic rubber, the emulsion also may contain, in addition to thesoap, a modifying agent such as an alkyl mercaptan, an activator such asan alkali metal pyrophosphate-ferrous salt composition, a peroxide-typecatalyst such as diisopropylbenzene hydroperoxide. As is well knownadditives may be present for other purposes and the above-mentionedadditives may be replaced with other compounds.

In the following examples all parts are by Weight. Reference is made inthese examples to use of the various soaps as an emulsifier in asynthetic rubber recipe. This basic recipe was as follows:

Parts by weight Preferably, solutions of portions of these ingredientsare prepared and then these solutions and the monomer are charged to thereactor in the desired order. In the following examples, an aqueoussolution of the soap and potassium chloride was prepared and adjusted toa pH value in the range of 10.5-10.8 with potassium hydroxide. Anactivator solution was prepared by combining aqueous solutions of theferrous sulphate and potassium pyrophosphate. The combined solutionswere heated to 60 C., held at this temperature for ten minutes and thenallowed to cool to room temperature. The mercaptan and the hydroperoxidewere dissolved in separate portions of the styrene. The soap solution,the styrene-mercaptan solution, the activator solution, and thebutadiene were charged to the reactor in the order named. The reactorcontents were agitated for minutes and then the hydroperoxide-styrenesolution was added. The timing of the reaction was started at this timeand the reactor contents were agitated while maintained at about 41 F.Samples were taken periodically and the percentage conversion ofmonomers to polymers calculated.

Example 1 Two polymerization runs were made utilizing theironpyrophosphate recipe previously described. In one run, the soap wasthe potassium soap of refined tall oil fatty acids in whichsubstantially all of the linoleic acid had been aromatized. These acidshad the following characteristics. Analysis was by vapor chromatography.

Acids: Percent Below C18 saturated 0.4 C18 saturated 6.6

C18 one double bond 75.0 C19 saturated 4.3 C18 two double bonds 3.2Aromatized linoleic acid 10.5

Note: C18 means a fatty acid containing eighteen carbon atoms in themolecule.

Properties Acid number 196 Iodine number 80 Titer, degrees centigrade 28In the second run the emulsifier was the potassium soap of a commercialgrade of oleic acid. In 4% hours the conversion with oleic acid soap asthe emulsifier was 45%, whereas, the conversion was 62.5% in the sameperiod with the soap of the fatty acids containing the aromatizedlinoleic acid.

Example 2 Two polymerization runs were made and in one the soap was thepotassium soap of a mixture in equal amounts of disproportioned tall oilrosin and the aromatized tall oil fatty acids of Example 1. In thesecond run the emulsifier was the potassium soap of a mixture in equalamounts of disproportioned rosin and hydrogenated tallow fatty acids. Inthe first run containing the soap of aromatized linoleic acid theconversion was 62.9% in 4% hours as compared to a conversion of 59.4% inthe second run containing the soap of hydrogenated tallow fatty acid.

Example 3 The emulsifier used in this run was the potassium soap of amixture of fatty acids containing aromatized linoleic acid. The fattyacid mixture prior to aromatiz-ation was a tall oil fatty acid fractioncontaining 14% unsaponifiable material, about 40% fatty acids similar topah'nitic acid, and substantial amounts of oleic acid and linoleic acid.The original acid mixture had an acid number of 178 and an iodine valueof 95. Aromatization of the linoleic acid reduced the iodine value to51. A 60% conversion was obtained in 4 hours.

' 4- Example 4 Aqueous solutions containing 3% of the potassium soaps ofdifferent fatty acids were prepared and then gradually cooled and thetemperature noted at which the soaps deposited on the cooling coils(plate out temperature). Thereafter, the solutions were gradually warmedto determine the temperature at which the soaps redissolved. Thefollowing results were obtained:

In the freeze-coagulation latex process oleic acid soaps have been usedin the past instead of hydrogenated tallow fatty acid soap as the oleicacid soap redissolves at a lower temperature and can be removed readilyfrom the coagulated rubber by washing. The freeze-coagulation process isused, for example, in the production of neoprene where thepolychloroprene latex is coagulated in a film on a freeze drum and thecoagulum removed and washed. The soaps of the present invention readilyredissolve at low temperatures and can be used in place of oleic acidsoaps, with or without rosin soaps, in such a freeze-coagulation processor in any other emulsion polymerization process which is carried out atrelatively low temperatures.

I claim:

1. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent an alkali metal salt of aromatized linoleic acid, saidalkali metal being selected from the group consisting of sodium andpotassium, and said aromatized linoleic acid being represented by theformula:

(CH CH (CH2) yC O OH wherein y represents a whole number of at least 5and less than 8 and x is equal to 10y.

2. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent an alkali metal salt of a mixture of acids comprisingaromatized linoleic acid and fatty acid containing from 14 to 20 carbonatoms, said mixture containing at least 5% by weight of aromatizedlinoleic acid and being substantially free of polyunsaturated fattyacids, said alkali metal being selected from the group consisting ofsodium and potassium, and said aromatized linoleic acid beingrepresented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10-y.

3. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent an alkali metal salt of a mixture of acids comprisingaromatized linoleic acid and fatty acid containing from 14 to 20 carbonatoms, said mixture containing at least 5% by weight of aromatizedlinoleic acid and at least 25% by weight of oleic acid, said mixturebeing substantially free of polyunsaturated fatty acids, said alkalimetal being selected from the group consisting of sodium and potassium,and said aromatized linoleic acid being represented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to y.

4. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, theimprovement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent the potassium salt of aromatized linoleic acid, andsaid aromatized linoleic acid being represented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10--y.

5. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent the potassium salt of a mixture of acids comprisingaromatized linoleic acid and fatty acid containing from 14 to carbonatoms, said mixture of acids containing at least 5% by weight ofaromatized linoleic acid and being substantially free of polyunsaturatedfatty acids, and said aromatized linoleic acid being represented by theformula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10y.

6. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent the potassium salt of a mixture of acids comprisingaromatized linoleic acid and fatty acid containing from 14 to 20 carbonatoms, said mixture of acids containing at least 5% by weight ofaromatized linoleic acid and at least by weight of oleic acid, saidmixture of acids being substantially free of polyunsaturated fattyacids, and said aromatized linoleic acid being represented by theformula:

"(CHzhCH (OH2)yC O OH wherein y represents a whole number of at least 5and less than 8 and x is equal to 10-3 7. In the production of linearpolymers by polymerization of a water insoluble, unsaturated organiccompound containing a CH =C group while dispersed in an aqueous mediumin the presence of an emulsifying agent under polymerization conditions,the improvement which comprises incorporating in said aqueous mediumprior to polymerization as an emulsifying agent the potassium salt oftall oil fatty acids containing at least 5% by weight of aromatizedlinoleic acid and containing less than 5% by weight of polyunsaturatedfatty acids, and said aromatized linoleic acid being represented by theformula:

(CHQXCHa "(CHDyO O OH wherein y represents a whole number of at least 5and less than 8 and x is equal to 10-y.

8. In the production of linear polymers by polymerization of a waterinsoluble, unsaturated organic compound containing a CH =C group whiledispersed in an aqueous medium in the presence of an emulsifying agentunder polymerization conditions, the improvement which comprisesincorporating in said aqueous medium prior to polymerization emulsifyingagents comprising (1) the alkali metal salt of aromatized linoleic acid,and (2) the alkali metal salt of disproportioned rosin, the alkali metalin each instance being selected from the group consisting of sodium andpotassium, and said aromatized linoleic acid being represented by theformula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10y.

9. In the polymerization of monomeric material comprising abutadiene-1,3, compound while dispersed in an aqueous medium in thepresence of an emulsifying agent under polymerization conditions toproduce synthetic rubber, the improvement which comprises incorporatingin said aqueous medium prior to polymerization as an emulsifying agentan alkali metal salt of aromatized linoleic acid, said alkali metalbeing selected from the group consisting of sodium and potassium, andsaid aromatized linoleic acid being represented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10y.

10. In the polymerization of monomeric material comprising abutadiene-1,3 compound while dispersed in an aqueous medium in thepresence of an emulsifying agent under polymerization conditions toproduce synthetic rubber, the improvement which comprises incorporatingin said aqueous medium prior to polymerization as an emulsifying agentan alkali metal salt of a mixture of acids comprising aromatizedlinoleic acid and fatty acid containing from 14 to 20 carbon atoms, saidmixture containing at least 5% by weight of aromatized linoleic acid andbeing substantially free of polyunsaturated fatty acids, said alkalimetal being selected from the group consisting of sodium and potassium,and said aromatized linoleic acid being represented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10-y.

11. In the polymerization of monomeric material comprising abutadiene-1,3 compound while dispersed in an aqueous medium in thepresence of an emulsifying agent under polymerization conditions toproduce synthetic rubber, the improvement which comprises incorporatingin said aqueous medium prior to polymerization as an emulsifying agentthe potassium salt of tall oil fatty acids containing at least by weightof aromatized linoleic acid and containing less than 5% by weight ofpolyunsaturated fatty acids, and said aromatized linoleic acid beingrepresented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to -y.

12. In the polymerization of monomeric material comprising abutadiene-l,3 compound while dispersed in an aqueous medium in thepresence of an emulsifying agent under polymerization conditions toproduce synthetic rubher, the improvement which comprises incorporatingin said aqueous medium prior to polymerization emulsifying agentscomprising 1) the alkali metal salt of aromatized linoleic acid, and (2)the alkali metal salt of disproportionated rosin, the alkali metal ineach instance being selected from the group consisting of sodium andpotassium, and said aromatized linoleic acid being represented by theformula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10- 13. In the polymerization of butadiene-1,3 and styrenewhile dispersed in an aqueous medium in the presence of an emulsifyingagent under polymerization conditions to produce synthetic rubber, theimprovement which comprises incorporating in said aqueous medium priorto polymerization as an emulsifying agent an alkali metal salt ofaromatized linoleic acid, said alkali metal being selected from thegroup consisting of sodium and potassium, and said aromatized linoleicacid being represented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10y.

14. In the polymerization of butadiene-l,3 and styrene while dispersedin an aqueous medium in the presence of an emulsifying agent underpolymerization conditions to produce synthetic rubber, the improvementwhich comprises incorporating in said aqueous medium prior topolymerization as an emulsifying agent an alkali metal salt of a mixtureof acids comprising aromatized linoleic acid and fatty acid containingfrom 14 to carbon atoms, said mixture containing at least 5% by weightof aromatized linoleic acid and at least by weight of oleic acid, saidmixture being substantially free of polyunsaturated fatty acids, saidalkali metal being selected from the group consisting of sodium andpotassium, and said aromatized linoleic acid being represented by theformula:

(CHz)xCH "(CHM wherein y represents a whole number of at least 5 andless than 8 and x is equal to 10-y.

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10-y.

16. In the polymerization of butadiene-1,3 and styrene while dispersedin an aqueous medium in the presence of an emulsifying agent underpolymerization conditions to produce synthetic rubber, the improvementwhich comprises incorporating in said aqueous medium prior topolymerization emulsifying agents comprising (1) the alkali metal saltof aromatized linoleic acid, and (2) the alkali metal salt ofdisproportionated rosin, the alkali metal in each instance beingselected from the group consisting of sodium and potassium, and saidaromatized linoleic acid being represented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10-y.

17. In the polymerization of chloroprene while dispersed in an aqueousmedium in the presence of an emulsifying agent under polymerizationconditions to produce polychloroprene, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent an alkali metal salt of aromatized linoleic acid, saidalkali metal being selected from the group consisting of sodium andpotassium, and said aromatized linoleic acid being represented by theformula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10- 18. In the polymerization of chloroprene while dispersedin an aqueous medium in the presence of an emulsifying agent underpolymerization conditions to produce polychloroprene, the improvementwhich comprises incorporating in said aqueous medium prior topolymerization as an emulsifying agent an alkali metal salt of a mixtureof acids comprising aromatized linoleic acid and fatty acid containingfrom 14 to 20 carbon atoms, said mixture containing at least 5% byWeight of aromatized linoleic acid and at least 25 by weight of oleicacid, said mixture being substantially free of polyunsaturated fattyacids, said alkali metal being selected from the group consisting ofsodium and postassium, and said aromatized linoleic acid beingrepresented by the formula:

(CHDyC O OH wherein y represents a whole number of at least 5 and lessthan 8 and x is equal to 10-y.

19. In the polymerization of chloroprene while dispersed in an aqueousmedium in the presence of an emulsifying agent under polymerizationconditions to produce polychloroprene, the improvement which comprisesincorporating in said aqueous medium prior to polymerization as anemulsifying agent the potassium salt of tall oil fatty acids containingat least by weight of aromatized linoleic acid and containing less than5% by weight of polyunsaturated fatty acids, and said aromatizedlinoleic acid being represented by the formula:

(C 2) x C a um and potassium, and said aromatized linoleic acid beingrepresented by the formula:

wherein y represents a whole number of at least 5 and less than 8 and xis equal to 10y.

References Cited by the Examiner UNITED STATES PATENTS 3/1959 Miller eta1. 26023.7

OTHER REFERENCES Floyd et al.: The Aromatization of Linoleic Acid WithPalladium Catalyst, The Journal of the American Oil Chemists Society,vol. 33, No. 12, December 1956, pp. 609-614.

LEON I. BERCOVITZ, Primary Examiner. DONALD E. CZAJA, Examiner.

J. J. KLOCKO, Assistant Examiner.

1. IN THE PRODUCTION OF LINEAR POLYMERS BY POLYMERIZATION OF A WATERISOLUBLE, UNSATURATED ORGANIC COMPOUND CONTAINING A CH2=C< GROUP WHILEDISPERSED IN AN AQUEOUS MEDIUM IN THE PRESENCE OF AN EMULSIFYING AGENTUNDER POLYMERIZATION CONDITIONS, THE IMPROVEMENT WHICH COMPRISESINCORPORATING IN SAID AQUEOUS MEDIUM PRIOR TO POLYMERIZATION AS ANEMULSIFYING AGENT AN ALKALI METAL SALT OF AROMATIZED LINOLEIC ACID, SAIDALKALI METAL BEING SELECTED FROM THE GROUP CONSISTING OF SODIUM ANDPOTASSIUM, AND SAID AROMATIZED LINOLEIC ACID BEING REPRESENTED BY THEFORMULA: